1. Field of the Invention
The present invention relates to a noodle cooker in which water in a pot is heated with a pulse combustor used as a heat source.
2. Description of the Related Art
Noodle cookers using a pulse combustor of a high thermal efficiency as a heat source have been proposed; for example, a combustion control unit for noodle cookers disclosed in Japanese Patent Laying-Open Gazette No. Sho-64-75816. This combustion control unit changes the ratio of combustion time to non-combustion time with a dial timer and controls the combustion conditions. Namely, the temperature of water in a pot is varied or maintained through regulation of the dial timer.
A preferable temperature range for boiling noodles is generally between 97.degree. C. and 98.degree. C. It is, however, difficult to keep the water temperature within the preferable range by such a timer control system since operation of the timer greatly depends on the experience of a user. In many cases, some amount of water is added to control the water temperature during the boiling process; however, the amount of water is also differed by the experience of a user. Insufficient water supply increases the water temperature to 100.degree. C., which causes overcooking of noodles. On the other hand, too much water supply decreases the water temperature lower than 97.degree. C., which causes undercooking of noodles.
A conventional pulse combustor, which continually ignites and combusts air and fuel mixture at a fixed cycle, includes a check valve both in a fuel gas supply system and an air fuel system to prevent back flow of combustion exhaust to the supply systems. In such a conventional pulse combustor, the amounts of fuel and air supply are determined by the volumes of a combustion chamber and supply conduits, and the turn-down ratio is thus not sufficiently high. This poor combustion efficiency of the conventional pulse combustor requires the troublesome and changeable dial control system to control the water temperature in the noodle cooker.